Marine Interpretation Message
Issued by NWS

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000
AGNT40 KWNM 031306
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
906 AM EDT SUN MAY 3 2015

.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.

GOES IR/VIS IMGRY INDC A LOW PRES SYS E OF THE OFSHR WTRS...AND A
FLAT RDG JUST W OF THE AREA...MOVG TO THE E. CRNT SFC RPRTS INDC
WNDS UP TO 30 KT...WITH THE HIGHEST OVR FAR NE NT2 IN THE W
QUAD/CAA OF THE LOW E OF THE AREA. HOWEVER...MOST OF THE
RPRTSCLOSER TO THE COAST ARE NO MORE THAN ABT 15 KT...AS HIGH PRES
BUILDS IN FM THE W. THE 00Z/06Z MDLS ALL INDC HIGH PRES WL BUILD
IN OVR THE WRN ATLC...AND DRIFT E THRU THE RGN INTO WED. THE 00Z MDLS
AGREE WELL IN THE SHORT...AND THE 06Z GUID HAS NOT CHANGED MUCH FM
THE 00Z CYCLE...SO NOT PLANNING ON MKG ANY SIG CHANGES IN THE
UPDATE PKG IN THE SHORT TERM.

THE BIGGEST FCST PRBLM CONT TO REVOLVE ABT THE LOW DVLPG OVR THE
FAR SRN WTRS THU. THE GLBL GEM CONT TO BE A STG OUTLIER...AND INDC
WINDS 50 KT OR GREATER BEFORE THE SYS MOVES INTO THE NC COAST NR
CAPE FEAR LATE THU NGT. THE GFS/ECWMF/UKMET ARE ALL SLOWER WITH
THE TRACK...AND ALSO WITH THE DVLPMT. THE GEFS/ECWMF ENSMBL MEMBER
STAY NR THEIR ASSOC OPER MDLS...SO ATTM PREFERRING THE SLOW/WKR
SOLN OF THE GFS/ECWMF. THE GFS DOES INDC A PD OF GALES...BUT ATTM
CONFDC IS SOMEWHAT LOW WITH THE HIGH UNCERTAINTY...SO WL CAP WNDS
AT 30 FOR THE FCST...AS WAS DONE IN THE PREV PKG. OTRW NOT
PLANNING ON MKG ANY MAJOR CHANGES.

-----------------------------------------------------------------
PREVIOUS DISCUSSION...

NEAR TERM...THE LATE EVE...0202Z...HI RES ASCAT PASS INDICATED
GALE FORCE WINDS OCCURRING OVR ZONE 910 WELL OFF THE MID ATLC
COAST. THIS WAS PRETTY MUCH IN LINE WITH THE PREV OFF FCST.
SATELLITE IMGRY SUGGESTS THAT THE LOW PRES AREA PRODUCING THESE
GALE FORCE WINDS HAS MOVED WELL E OF THE OFF WTRS...OR OVR 500 NM
E OF CAPE HAT. THE LOW IS ALSO SHOWING SIGNS OF WEAKENING. AS A
RESULT...WE WILL ALLOW THE GALES TO END WITH THE ISSUANCE OF THE
EARLY AM FCST PACKAGE. HIGH PRES WILL TAKE CONTROL OF CONDITIONS
OVR THE OFF WTRS TODAY...AND PERSIST INTO MON AS THE LOW TRACKS
FURTHER E AWAY FROM THE WTRS. A COLD FRONT WILL APPROACH THE NEW
ENGLAND COAST FROM THE NW MON NITE. THE FRONT WILL CROSS NT1 OFF
WTRS TUE...STALL NEAR 39-40N TUE NITE...AND THEN DSIPT WED AS LOW
PRES ORGANIZES TO THE S OF THE OFF WTRS. THE 00Z GFS HAS REMAINED
QUITE CONSISTENT OVR THE PAST FEW CYCLES AND HAS GOOD SUPPORT
FROM THE 00Z NAM...00Z UKMET AND 00Z ECMWF MDLS FOR TODAY THRU
WED. AS A RESULT...WE WILL STAY CLOSE TO THE 30M GFS WINDS FOR
THIS MORNING AS COLD AIR ADVECTION PERSISTS OVR ESPEC NT2 WTRS TO
THE W OF THE LOW PRES AREA NOTED ABV. FOR THE AFTERNOON HOURS
INTO WED WE WILL TRANSITION TO USING THE 10M GFS WINDS AS WE FEEL
THEY WILL BE MORE REPRESENTATIVE OVR THE WTRS AS HIGH PRES
CROSSES THE REGION...AND A WEAK COLD FRONT DROPS INTO THE NEW
ENGLAND WTRS TUE.

LONG TERM...AGAIN THE FOCUS FOR WED NITE THRU THU NITE WILL BE THE
POTENTIAL FOR LOW PRES ORGANIZING S OF THE NT2 WTRS EARLY
THU...AND THEN POTENTIALLY LIFTING N INTO THE WTRS LTR THU INTO
FRI. THE 00Z MDL GUID REMAINS IN POOR AGREEMENT WITH THE FUTURE
PSN AND INTENSITY OF THIS LOW PRES SYSTEM BY LATER IN THE WK. THE
00Z CANADIAN MDL DEEPENS THE LOW TO NEAR 1000 MB OFF THE COAST OF
CAPE FEAR BY 00Z FRI...WHILE THE 00Z GFS KEEPS A 1008 MB LOW
FURTHER S TOWARD 30N 78W...WITH THE 00Z UKMET HAVING A 1014 MB
LOW FURTHER TO THE SE NEAR 29N72W BY 00Z FRI. THE 00Z GFS HAS
TRENDED SLOWER AND WEAKER WITH THE LOW COMPARED TO ITS PREV FEW
MDL RUNS. AT THIS TIME WE WILL IGNORE THE 00Z CANADIAN MDL AS IT
APPEARS TO BE TOO STRONG AND TOO FAR N WITH THE LOW LATE IN THE
WK. THE 00Z GEFS MEAN WOULD INDICATE THAT A WEAKER SOLUTION
APPEARS MORE LKLY AT THIS TIME. THEREFORE WE WILL STAY THE COURSE
AND STAY WITH THE WEAKER 00Z UKMET AND 00Z ECMWF SOLUTIONS FOR
THE WED NITE THRU THU NITE TIME FRAME.

SEAS...SEA HTS APPEAR TO BE RUNNING ABOUT A FT OR SO ABOVE BOTH
THE 00Z WNA WAVE WATCH III MDL AND 00Z ECMWF WAM WV MDL GUID PER
THE 06Z RA1 SEA STATE ANALYSIS. FOR THE EARLY AM PACKAGE WE WILL
AGAIN USE A 50-50 BLEND OF THE WAVE WATCH III AND ECMWF WAM WV
GUID FOR TODAY THRU WED...AND THEN TRANSITION TO USING JUST THE
ECMWF WAM WV GUID WED NGT THRU THU NGT AS WE USE THE WEAKER 00Z
ECMWF AND UKMET MDL WIND GUID FOR THAT TIME FRAME AS NOTED ABV.
INITIALLY WE WILL ADJ GRIDS ACCORDINGLY TO FIT THE LATEST OBS.

.EXTRATROPICAL STORM SURGE GUIDANCE...THE LATEST ETSS AND ESTOFS
MDL GUID SUGGESTS THAT NO SIG SURGE EVENTS ARE LKLY OVR THE REGION
FOR THE NEXT FEW DAYS. THE SURGE MDL GUID MAY BE OVERDONE BY MID-
LATE WK AS THE GUID IS RUN OFF THE GFS WINDS AND WE WILL
TRANSITION TO USING THE UKMET AND ECMWF WINDS WHICH ARE WEAKER.


.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER KELLS/MILLS. OCEAN PREDICTION CENTER.



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